The bulbourethral glands or Cowper's glands (named for English anatomist William Cowper) are two small exocrine

gland In animals, a gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream ( endocrine gland) or into cavities inside the body or its outer surface ( exocrine gland). Structure ...

s in the reproductive system of many

male mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

(of all domesticated animals, they are absent only in dogs). They are homologous to

Bartholin's gland The Bartholin's glands (named after Caspar Bartholin the Younger; also called Bartholin glands or greater vestibular glands) are two pea sized compound alveolar glandsManual of Obstetrics. (3rd ed.). Elsevier. pp. 1-16. . located slightly poster ...

s in females. The bulbouretheral glands are responsible for producing a pre-ejaculate fluid called

Cowper's fluid Pre-ejaculate (also known as pre-ejaculatory fluid, pre-seminal fluid or Cowper's fluid, and colloquially as ''pre-cum'') is a clear, colorless, viscous fluid that is emitted from the urethra of the penis during sexual arousal. It is similar in ...

(known colloquially as ''pre-ejaculate'' or ''pre-cum''), which is secreted during sexual arousal, neutralizing the acidity of the urethra in preparation for the passage of sperm cells.

Location

Bulbourethral glands are located posterior and lateral to the membranous portion of the

urethra The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra con ...

at the base of the penis, between the two layers of the

fascia A fascia (; plural fasciae or fascias; adjective fascial; from Latin: "band") is a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches to, stabilizes, encloses, and separates muscles and other internal organs ...

of the urogenital diaphragm, in the deep perineal pouch. They are enclosed by transverse fibers of the

sphincter urethrae membranaceae The urethral sphincters are two muscles used to control the exit of urine in the urinary bladder through the urethra. The two muscles are either the male or female external urethral sphincter and the internal urethral sphincter. When either of th ...

muscle.

Structure

The bulbourethral glands are compound tubulo-alveolar glands, each approximately the size of a pea in humans. In

chimpanzees The chimpanzee (''Pan troglodytes''), also known as simply the chimp, is a species of great ape native to the forest and savannah of tropical Africa. It has four confirmed subspecies and a fifth proposed subspecies. When its close relative the ...

, they are not visible during dissection, but can be found on microscopic examination. In

boars The wild boar (''Sus scrofa''), also known as the wild swine, common wild pig, Eurasian wild pig, or simply wild pig, is a suid native to much of Eurasia and North Africa, and has been introduced to the Americas and Oceania. The species i ...

, they are up to 18 cm long and 5 cm in diameter. They are composed of several

lobules In anatomy, a lobe is a clear anatomical division or extension of an organ (as seen for example in the brain, lung, liver, or kidney) that can be determined without the use of a microscope at the gross anatomy level. This is in contrast to t ...

held together by a fibrous covering. Each lobule consists of a number of

acini An acinus (; plural, acini; adjective, acinar or acinous) refers to any cluster of cells that resembles a many-lobed "berry," such as a raspberry (''acinus'' is Latin for "berry"). The berry-shaped termination of an exocrine gland, where the s ...

, lined by columnar epithelial cells, opening into a duct that joins with the ducts of other lobules to form a single excretory duct. This duct is approximately 2.5 cm long and opens into the bulbar urethra at the base of the penis. The glands gradually diminish in size with advancing age.'' Gray's Anatomy'', 38th ed., p 1861.

Function

The bulbourethral gland contributes up to 4 ml of fluid during sexual arousal. The secretion is a clear fluid rich in

mucoprotein A mucoprotein is a glycoprotein composed primarily of mucopolysaccharides. Mucoproteins can be found throughout the body, including the gastrointestinal tract, reproductive organs, airways, and the synovial fluid of the knees. They are called muco ...

s that help to lubricate the distal

and neutralize acidic

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular m ...

which remains in the urethra. According to one preliminary study, the bulbourethral gland fluid might not contain any

sperm Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, wh ...

, whereas another study showed some men did leak sperm in potentially significant quantities (in a range from low counts up to 50 million sperm per ml) into the pre-ejaculatory fluid, potentially leading to conception from the introduction of pre-ejaculate. However, the sperm source is a residual or pre-ejaculatory leak from the testicles into the vas deferens, rather than from the bulbourethral gland itself.

Gallery

File:Illu penis.jpg, Structure of the penis File:Gray1136.png, Male pelvic organs seen from right side. File:Gray1156.png, Vertical section of bladder, penis, and urethra. File:Gray543.png , Bulbourethral gland labeled at center left.

References

{{DEFAULTSORT:Bulbourethral Gland Exocrine system Glands Mammal male reproductive system

Location

Structure

Function

Gallery

See also

References